240 SUMMARY OF CURRENT RESEARCHES RELATING TO 



continuous layer of protoplasm, tlie presence of whicli was wrongly- 

 denied by Ludwig ; this layer becomes distinctly marked off into 

 germinal areee ; this division is due to the protoplasm being taken 

 into the interior from the surface of the egg. Hyaline protoplasm 

 becomes intercalated between the yolk-spheres of the surface. This 

 phenomenon has no special influence on the formation of the 

 blastoderm ; it is rather the result of a centrifugal action of the 

 protoplasm. 



After criticizing some of the observations of Ludwig, the author 

 says that, in the Araneina, the protoplasm passes from the centre to 

 the periphery, where it appears under the form of discs or " conea 

 dejection," surrounded by a wreath of spheres. This process divides 

 the ovum into a meroblastic egg, with a number of cicatriculfe. In 

 the second period of its history the egg gives rise to a second 

 generation of similar cells. The superficial protoplasm continues to 

 segment, and finally forms a simple layer of flattened polygonal 

 cells. The observations of the author combat in many points the 

 results of Ludwig. 



S. Crustacea. 



Crustacea from the Gulf of Mexico and the Caribbean Sea.*— 

 In his preliminary communication, M. A. Milne-Edwards describes a 

 large number of new genera and species. 



Trachymaia (near Halimus and Amathia) is represented by 

 T. cornuta. Lispognaihus is intermediate between Eiiprognatlm and 

 Anisonotus : L. furcatus. Anasimus [A. fugax) is allied to Podochela 

 and Anisonotus. 



Among the Carcinoplacida, we have Frevillea with F. barhafa, 



F. rosea, F. Sigshei, and F. tridentata. The blind Batkyplax is allied 

 to Carcinoplax : B. typhlus. Eucratoplax is intermediate between the 

 Panopceidce and Euryplax : E. guttata and E. elata. 



Trichopelt avion (T. nohile) is a new genus of the Oxystomata. 



In the Dorippidce, we have Corycodus, with a globular carapace : 

 C. hullatus. Cyclodorippe [C. nitida, G, antennaria, and C Agassizii) 

 is like Cymononms (C. quadratus) and Cymopolus (C. asper) inter- 

 mediate between the Dorippidas and the abnormal Brachyura. 



In the Dromiadce there appears Acanthodromia (A. erinacea), 

 which is intermediate between Dromia and Dynomene ; and Dicra' 

 nodromia (D. ovata); Homolodromia {H. paradoxa), and Homolopsis 

 (H. rostrata^. 



Baninops (B. constridus, B. Stimpsoni) is a new Eaninid. 



In the Pagurida, we have Xylopagurus (X. rectus) ; Pylocheles 

 (P. Agassizii) is near Pomatocheles ; Mixtopngurus (M. paradoxus) 

 allies Pagurus with Pylocheles. Ostraconotus {0. spatuUpes) has the 

 carapace entirely coriaceous. Catapagurus is intermediate between 

 Ostraconotus and Spiropagurus (C. Sharreri). 



In the Macrura, we have Galacantha (G. rostrata, G. spinosd) ; 

 Galathodes (G. erinaceus, G. spinifer, G. robustus, G. serratifrons, 



G. abbreviatus, G. Beynoldsi, G. simplex, G. Sigsbei, G. latifrons, 



* Bull. Mas. Comp.^Zool. Camb., viii. (1880) rp. 1-68(2 pla.). 



