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Show 1889.] ANATOMY OF GONATUS FABRICII. 133 From this table we may extract the following sets of resemblances and differences:- A. Gonatus resembles both Onychoteuthis and Enoploteuthis in :- (2) the fact that the club of the tentacle has both hooks and suckers, though it differs widely in their arrangement; (5) the fact that the funnel has a valve and a funnel-organ; (6) the simple siphono-pallial articulation ; (16) the number (though not the disposition) of the oviducts. B. Gonatus resembles Onychoteuthis and differs from Enoploteuthis in :- (4) the extension of the fins beyond the end of the body proper; though even here a difference in their relation obtains owing to the varying form of the pen, which, however, has a phragmocone in both; (9) the fusion of the middle portions of the median retractors of the head; (11) the absence of the nuchal muscle ; (12) the form of the median tooth of the radula ; (18) the presence of nidamental glands. C. Gonatus resembles Enoploteuthis and differs from Onychoteuthis in : - (10) the separation between the median and lateral retractors of the head; (13) the rudimentary anterior salivary glands; (14) the symmetrical anal appendages ; (17) the situation of the oviducts dorsal to the roots of the gills. D. Gonatus differs from both Onychoteuthis and Enoploteuthis i n :- (1) the arrangement of suckers in 4 rows and in their armature; (2) the details of armature of the tentacular club ; (3) the connective apparatus of the tentacles; (4) the exact relation of the end of the body to the fins; (7) the presence of a siphonal cartilage ; (8) the form of the pen ; (12) the radula; (15) the absence of accessory hearts. In regard to A the most noticeable fact is that no points of importance have been elucidated in which Gonatus resembles both the other forms under consideration except such as are also common to a much larger number of forms. The characters grouped under D are, I think, sufficient to justify the step taken three years ago in making this genus the type of a new subfamily Gonatidee, for there can be no doubt that it is incomparably further removed from Onychoteuthis and Enoploteuthis than they are from each other. The question which of these two genera it more nearly resembles is more difficult to settle ; but I should be disposed on the whole to attribute more weight to the characters which ally it to Onychoteu- PROC. ZOOL. Soc-1889, No. X. 10 ' |