ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 207 



New Cephalopoda.* — A. E, Verrill, in a supplement to his ' Blake 

 Eeport' describes, among others, the representatives of two new 

 genera. NedoteutMs is allied to Stoloteuthis, but he weakens the effect 

 of his discovery by remarking that " some of the peculiar features of 

 the arms and suckers may be only sexual." OpisihoteuiJiis is most 

 remarkable for the posterior opening of the siphon and branchiae, 

 which is in correlation with the union of the head and body with the 

 brachial membrane. Both of these new genera are founded on single 

 specimens, and in neither case was the sex of the individual absolutely 

 certain. 



Two new species of Octopus, 0. punctatus and 0. himaculatus, are 

 described in a succeeding communication ; with regard to the former 

 the observations of Mr. Dall are of great interest. " When angry, 

 the horn over the eye is erected, the arms coil together, the eye 

 dilates, and the body quivers with rage. The muscles keep up a 

 squirming motion, but I have never seen any approach to the dark 

 colour figured by Chenu as characteristic of the angry Octopus vulgaris 

 of the Mediterranean, nor any such elevated longitudinal ridges. The 

 suckers project or are retracted according to the mood of the animal ; 

 their outer edge expands when about to seize hold, and contracts after 

 getting hold of anything. ... It never willingly turns its mouth up, 

 and when forced to do so clenches its arms, like a fist, over it. With 

 death comes flaccidity and flattening. One with a body 8 in. in 

 diameter had the arms 16 ft. long. They shrank much in alcohol." 

 The second species, as represented by its largest known male, has the 

 dorsal arms 325 and 390 mm. long from the mouth ; the second pair 

 540 and 450 mm. ; the ventral arms 500 and 490 mm. The diameter 

 of the larger suckers of the lateral arms was 11 to 14 mm. ; the body 

 was 70 mm. long, and where broadest, 75 mm. 



Operculum of Gasteropoda.f — M. Houssay has investigated the 

 question as to what part of the foot of gasteropods excretes the 

 substance of the operculum, and how the growth of that organ is 

 effected. The term columellar border is applied to that portion of the 

 operculum which is found near the columella of the shell, and that of 

 parietal harder to the opposite edge. The internal and external 

 surfaces of the operculum are not formed in the same way. In the 

 latter there is a small transverse cleft, the walls of which are lined 

 by a special epithelial layer, which soon dries in air and becomes of a 

 horny consistency. The cells of the layer secrete a structureless 

 material which gives rise to a hyaline membrane ; this escapes by the 

 cleft and becomes added on to the operculum ; as these are successively 

 laid down the outer face of the operculum is striated. The inner 

 surface is clothed by an apparently homogeneous layer. The spiral 

 form of the operculum seems to be due to the slight rotation to which 

 it is subjected as the shell grows, and the consequent alteration in 

 position of the columellar muscle. The organ in question is produced 

 by a part only of the epithelium of the foot, and, while it has 



* Bull. Mus. Comp. Zool., xi. (1883) pp. 105-24 (6 pis.), 

 f Oomptes Kendus, xcviii. (1884) pp. 236-8. 



