ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 169 



Spider. The two forms — known as the tufted and the grey — appear to 

 be approximately equal in numbers, and the total number of males 

 collected (70) was not far short of the total number of females collected 

 (80). The tufted males differ from the others in the colour of the 

 legs, the colour of the palps, and in the possession of three tufts of hair 

 on the cephalothorax. They also differ in the method of their love 

 dance, but the females show no preference. The dimorphism is probably 

 due to a discontinuous variation. It was found that the grey males 

 carried a pair of small chromosomes, called " ctetosomes " by the author, 

 while the nuclei of the tufted males lacked these elements. 



Food-canal of Limulus.* — D. H. Wester finds that in the oesophagus, 

 stomach, and a small hind-gut portion of Limulus there is a chitinous 

 lining ; there is none in the long mid-gut ; the same is true in Mygah 

 avicularia and Epeira diadema. No chitin was found in the gut of 

 Scorpio and Buthns, nor in Tegeneria domestica and another spider. In 

 Astacus, Hyas, Carcmus, the whole alimentary canal shows, according to 

 the author, a chitinous lining. (This is difficult to credit in regard to 

 the mesenteron ; and of Eupagurus bernhardus the author says that he 

 is not sure if " the portion of the gut immediately behind the stomach" 

 is chitinous.) The conclusion drawn is that Limidus is related to 

 Arachnoids rather than to Crustaceans. 



Regeneration in Pantopoda.f — W. Schimkewitsch and V. Dogiel 

 have studied the regeneration of appendages in species of Nymphon, 

 Anoplodactylus, Chsetonymphon, Pycnogonnm, and other forms. There 

 is evidence of the regeneration of the cheliferaa, probably of the palps 

 and ovigerous limbs, of the posterior limbs, and of the abdomen. The 

 re-grown appendage may be like the original or after a primitive type. 

 The regeneration of the cheliferse may be quite abnormal. Sometimes 

 the regenerating part shows some duplication. 



Development of Pantopoda. $ — V. Dogiel has made an important 

 contribution to the embryology of the Pantopoda. He distinguishes 

 three types of development, as ' exemplified : (1) by Anoplodactylus 

 PhoxichUidium and Pycnogonum ; (2) by Nymphon stromii ; and 

 (3) by Chsetonymphon spinosum. The post-embryonic development and 

 metamorphosis is described in six types, and the organogenesis of the 

 larva. Some general results may be noted. 



The segmentation is total, and, to begin with, equal. It afterwards 

 becomes unequal. The result is a cceloblastula or a sterroblastula. 

 Gastrulation occurs by typical epibole or by a process intermediate 

 between epibole and invagination. The development is definitely 

 determinate, particular cells forming particular layers, but the yolk in 

 some types tends to disguise this. There is a strong resemblance 

 between the early development of Pantopoda and that of some Ento- 

 mostraca. This is well illustrated by the history of the endoderm. 



* Zool. Jahrb., xxxv. (1913) pp. 637-9. 



t Bull. Acad. Imp. Sci. St. Petersbourg (1913) No. 18, pp. 1147-56 (10 figs.). 



% Zeitschr. wiss. Zool., cvii. (1913) pp. 575-741 (6 pis. and 109 figs.). 



