ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 931 



red Decapod measuring more than 28 feet was observed in 1886 at Cape 

 Campbell, New Zealand. 



Germinal Layers in Cephalopods.* — Mr. S. Watase gives a more 

 detailed account of bis investigations on the homology of the germinal 

 layers in Cepbalopods (Loligo pealii). His more important results in 

 regard to the " yolk-membrane " and the phenomenon comparable to an 

 epibolic gastrula have already been reported. f 



The " yolk-membrane " is a true endoderm and its sole representative 

 in the Cepbalopods. The digestive tract with its appendages is entirely 

 formed by the ectodermic invaginations, by the prolongations of the 

 proctodeeum and stomodseum. At no period of develoi^ment is there 

 any connection between the " yolk-membrane " and the digestive tract, 

 and long before the absorption of the food-yolk is completed the 

 permanent digestive canal is formed. With the absorption of the food- 

 yolk the "yolk-membrane" disappears. 



The consequences of the gradual increase in the size of the yolk, as 

 emphasized by Eyder for the Vertebrate series, apply with equal force 

 in the Molluscs. " The endoderm in the highest group, the Cephalopoda, 

 is made a temporary embryonic structure which may be said to have no 

 chance of leaving traces of definite structure in the organization of the 

 adult, and the set of secondary digestive organs in addition to the 

 primary one is developed from an entirely diiferent source, the ecto- 

 derm." This may possibly be an extreme instance of the influence 

 which the food-yolk exerts in modifying the course of development and 

 the history of the germ-layers. 



Olfactory Ganglia of Gephalopods.^— Sig. G. Jatta has investigated 

 the so-called olfactory ganglia of Cepbalopods, and comes to the following 

 conclusions : — (1) The so-called olfactory ganglia include a true ganglion 

 and a mass of connective tissue; (2) the ganglion is united to the 

 cerebral by means of nerve-fibres ; (3) it may be considered as accessory 

 to the otic ganglion; (4) the mass of connective tissue which in the 

 Cepbalopods with more evolved nervous system tends to be less distinct 

 from the ganglion to which it adheres, may perhaps be regarded as itself 

 representing a ganglion, which tends to disappear with cessation of 

 function. 



Continuing his observations § he discusses the origin of the olfactory 

 nerve. His investigations were based on Sepia, Loligo, Eledone, and 

 Octopus, and warranted him in concluding that the olfactory nerve of 

 Cepbalopods arises from the supra-oesophageal ganglion, called by Dietl 

 the superior frontal ganglion. 



Some Oigopsid Cuttle-fishes. |j — Mr. P. E. Weiss has made a careful 

 examination of the cuttle-fishes in University College, London. He has 

 studied, among the Oigopsida, ChiroieuthisVermiyi, Doratopsis vermicularis, - 

 HistioteutMs Bueppelli, Tracheloteuthis Behni, and Verania sicula. He 

 comes to the conclusion that the family Chiroteuthidfe should be re- 

 tained, but not on the grounds formerly given, namely the absence of 

 siphonal valve, loss of accessory nidamental glands and of one of their 

 oviducts. The various leading points of agreement are pointed out. 



* Stud. Biol. Lab. Johns-Hopkins Univ., iv. (1888) pp. 163-83 (2 pis ) 

 t This Journal, 1888, pp. 396-7. 



J Bull. Soc. Nat. Napoli, i. C1887) pp. 30-33. § Ibid., pp. 92-3 



II Quart. Journ. Micr. Sci,, xxix. '1888) pp. 75-96 (3 pis.). 



