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Show 376 SIR C. ELIOT ON NUDIBRANCHS [Dec. 1, larger than the others. The branchiae are six, tripinnate, very ample and delicate. The tufts at the side of the posterior pair are almost separate, so that the whole number might be reckoned as eight. The rhinophore-pockets are closed by indistinct crenula-tions. The oral tentacles are of a fair size, white and conical. There is no trace of labial armature. The radula formula is about 48 x 60.0.60. The teeth are simply hamate, the innermost smaller, the two or three outermost irregular. The penis is armed with the hamiferous disks characteristic of the genus apparently set in four rows, and the vagina provided with strong folds. The animal, both when alive and when preserved, is exceedingly hard and rough. It is very sluggish, and I have always found it fitted into crevices on the underside of stones, as if it had not moved for a long period. 20. PLATYDORIS FORMOSA ? (A. & H.), var. [Alder & Hancock, " Notes on a Coll. of Nudibr. Moll, made in India," Tr. Z. S. iii. 1864, p. 116.] One specimen from Chuaka. The notes on the living animal describe it as bright scarlet, shaded in places by minute brown specks, very flat, and rough to the touch all over. The end of the mantle had been thrown off, probably by self-mutilation, so that the body terminated abruptly behind the gill-pocket. The alcoholic specimen is much bent, but if straightened out would be about 5 centimetres long ; the maximum total breadth is 4 and the maximum width of the mantle margin 1*4. The somewhat projecting rhinophore-pockets have slightly crenulate edges, as has also the branchial pocket, which is nearly round. The branchiae are six, tripinnate, and rather small. The foot is somewhat broader than usual in the genus, grooved and notched in front. The oral tentacles are large and slightly grooved on the outer side. The buccal mass is very large and muscular. There is no labial armature but a large dark radula, consisting of simply hamate teeth, the innermost smaller, the outermost irregular in shape. The formula is about 60.0.60 X 40. The genital organs are very strong and muscular, the male branch set with numerous yellow hooks of the shape usual in the genus : the female branch with strong folds and lumps. I think this specimen may be referred to PI. formosa, or at least that there is not sufficient ground for creating a new species. It is certainly not PI. arrogans {cruenta), which has scarlet blotches but a pattern formed by minute dark lines, not spots. Allowing for the variations so common in this genus, the coloration corresponds fairly well with Alder and Hancock's description, and the grooved tentacles are a remarkable point in common. The chief discrepancy is that the branchial pocket is not distinctly lobed or stellate, as in the typical PI. formosa; but I have noticed in many species of Platydoris that though on an average this character may be very well marked, it may be indistinct in some individuals. |
