OCR Text |
Show 200 MR. P. S. ABRAHAM ON THE [Mar. 6, tacles (rarely absent); odontophore broad, with numerous spines in each transverse row. The genus is very similarly characterized in the Appendix to Messrs. Alder and Hancock's monograph. In the text of that work, however, " Doris " is made to include Doris proper, Lamellidoris, and Acanthodoris as sections. There can be little doubt that the internal and external distinctions of the three groups are really sound generic differences. The following subdivisions of the restricted genus Doris were proposed by Alder and Hancock ; - " a. Dorsal tentacles conical; oral tentacles tubercular ; cloak with hard spiculose tubercles. Lingual spines simple, uniform; no central spine. Type D. tuberculata, Cuv. " b. Dorsal tentacles conical ; oral tentacles tubercular ; cloak with soft tubercles. Lingual spines long, linear, obtuse, denticulated; no central spine Type D. zetlandica, A. & H . " c. Dorsal tentacles clavate ; oral tentacles linear; lingual spines of two forms; no central spine Type D. johnstoni, A. & H. " d. Dorsal tentacles linear; oral tentacles angular, flattened. Lingual spines denticulated ; a small central spine. Mouth with a spinous collar. Type D. repanda, A. & H. " e. Dorsal tentacles conical, partially retractile, and protected by leaf-like appendages; oral tentacles linear or tubercular; branchiae linear, simply pinnate; cloak with large tubercles. Lingual spines simple, uniform ; no central spine. Glossodoris, Ehr D. verrucosa, Cuv. "f. Dorsal tentacles conical; oral tentacles leaf-shaped; branchia? each with several pinnate rays branching from a foot-stalk ; cloak very large, flat and coriaceous. Lingual spines ? Actinodoris, Ehr. D. cruenta, Qu. & G. "y. ? With only two tentacles; branchia? in front of anus, not surrounding it. Lingual spines ? Actinocyclus, Ehr A. vetulinus, Ehr. " h. ? Dorsal tentacles truncated ; branchia? small; cloak large, carinated on the back. Lingual spines? Atayema, Gray D.carinata,Clu.&G." So far as we at present know, perhaps 9 species may be referred to division a, one to division b, four to c, and two to d. Division e corresponds with the genus " Doridigitata," D'Orbigny, or " Glossodoris" Gray (non Ehrenberg), and includes four species. The group f supposed to be synonymous with " Actinodoris" Ehr., can scarcely be maintained; for many of the species which have been referred to it are probably Doridopsidae, and D. cruenta, which Alder and Hancock have taken for the type, undoubtedly belongs to the " As-teronotus" group. Division h contains but one species. This arrangement gives no place to a large number of Dorides which have the common characters of a depressed coriaceous body, wide and granular mantle, rhinophores clavate and retractile in denticulate-edged sheaths, oral tentacles linear or slightly flattened, branchiae six, retractile in a cavity protected by six lobular marginal processes, lingual spines simple, uniform, none central-and the type of which is Asteronotus hemprichii, Ehr. After using all the above sections, "*e should still have left some 90 species or so, which either do not fie into any of them, or which have been too scantily characterized for us to determine their position. A great many of the published descriptions of these animals are so meagre and superficial, often |