486 SUMMARY OF CURRENT RESEARCHES RELATING TO 



correct, we find in it what may be spoken of as parallel-developments 

 with the Myopsida and Octopoda ; we find, that is, in this side 

 branch a series of differentiations which have, for the different organs, 

 a most remarkable resemblance in those two series. Just as from 

 Loligo to Sepia, so from Bossia to Sepiola we find the upper salivary 

 glands lost, the accessory nidamental glands fused, the efferent duct 

 of the ink-bag sharply marked off, and the lateral teeth disappearing 

 from the middle plate of the radula. From Ommastrephes to Sepia, 

 just as from Bossia to Sepiola, the fused lower salivary glands are 

 separated, and there appears a characteristic arrangement of the ova 

 in the duct. Likewise, there is in Sepia and Bossia a shortening of 

 the inner pallial nerves, which finds its termination in the absence 

 of these in Sepiola on the one hand, and the Octopoda on the other. 

 A very instructive diagrammatic table is given by the author to 

 demonstrate the points on which he insists. 



If we enter into still wider generalizations, the facts observed by 

 the author lead us to see that in the Dibranchiate Cephalopoda, long 

 before the separation of the phylum into the Octopoda and Decapoda, 

 there must have been a tendency, under suitable, though still un- 

 known, conditions, for the cartilaginous articulations with the mantle 

 and funnel to yield to firmer membranous or muscular cephalic 

 joints ; thrice, or twice at least, did this tendency exert its influence. 

 In connection with this there must' also have been a tendency to the 

 reduction and final loss of the upper salivary glands, the separation 

 of the lower ones, and the fusion of the accessory nidamental 

 glands. 



Dr. Brock then passes to a second study of the generative organs 

 of the Cephalopoda ; in dealing with the female organs of the 

 CEgopsida it is pointed out that the nidamental glands may be absent, 

 as in Enoploteuthis, or that they may be present, with (a) the oviduct 

 lying ventrally to the gills, as in Ommaslreplies sagittatus, or (/5) the 

 oviduct may open with a buccal invagination of the integument, lying 

 dorsally to the gills, as in Om. todarus, Onychoteuthis, or Thysano- 

 teuthis. 



A study of the generative organs of the Philonexidae shows , us 

 that they may be thus arranged : — 



1. Subfam. HectocotylifergB. $ with a free Hectocotylus. 



a. Philonexida3 S. Str. Hectocotylus without dermal frills. 



No water-vascular system — Argonauta, Philonexis. 

 o. Tremoctopodidae. Hectocotylus with dermal frills. A 



water-vascular system — Tremociopus. 



2. Subfam. Parasiridse. Free hectocotylus not known, but pro- 



bably present. $ with very long oviducts, viviparous. 

 Parasira. . 

 In dealing with the gland of the oviduct, it is pointed out that 

 the following series may be detected in the Octopoda : — 



1. Gland consisting of a series of caeca arranged radially around 

 the oviduct; no increase in the extent of the secreting surfaces 

 — Argonauta. 



2. The secreting surfaces of the gland well developed, and a 



