7i4 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Significance of the Larval Skin in Decapods.* — H. W. Conn 

 discusses the phylogenetic significance of t£e peculiar structure 

 inclosing embryos of Crustacea known as the larval skin. This 

 skin being probably of no physiological importance, is therefore 

 particularly valuable in its morphological significance. 



A number of new types of larval skin ajre described (CalUnedes, 

 Sesarma, Pinnotheres), and it is shown that there is a complete and 

 graduated series beginning with a form like Panopeus, where the 

 larval skin is a highly complex structure with many feathered spines, 

 and ending in a form like Pinnotheres, where the cuticle is nothing 

 more than a larval covering with no spines. In general also it is 

 found that the more complex larval skin is found in crabs, which, 

 stand low in classification, while the simple larval covering is found 

 in more highly organized Brachyura ; a condition of things just as 

 we should expect from the consideration that this structure represents 

 the ecdysis of some stage in the crab development earlier than the 

 zoea. It is further shown that such an earlier stage was probably a 

 protozoea and that we, therefore, have here strong evidence that this 

 stage was formerly included in the ontogeny, and therefore in the 

 phylogeny of the Brachyura. Finally it is argued that evidence is 

 here obtained tending very strongly to show that the Decapod zoea is 

 simply a larval form which has never been represented in the phylo- 

 genetic history of the group, contrary to what has been claimed by 

 Miiller, and later in a difierent form by Balfour. 



New or Rare Crustacea.f — In his Sdth article on this subject 

 M, Hesse describes five new Crustacea belonging to the order which 

 he has called that of the Eostrostomata ; like the Siphonostomata, 

 they are found on the skins of the Squalidee, but, unlike them, they 

 have not a rigid tubuliform mouth by means of which they can 

 penetrate the thick skin ; the paouth is rather obtuse and soft, and 

 the animals, therefore, make their way into the branchial cavity, where 

 they are sheltered and early obtain a rich supply of food. 



The new species, of which the females are alone known, are called 

 Kroyeria galei vulgaris, Eudactylina squatince angeli, Eudactylus 

 jnusteli Icevis, E. charcharice glauci, and Pagodina charcharice glauci. 

 The author concludes with some observations on the systematic 

 position of these species. 



Vermes. 



New Type of Hirudinea.J — MM.Poirier and A. T. de Eochebrune 

 describe a new type of Hirudinea which they found attached not 

 pnly to the mucous membrane of the mouth of Crocodilus vulgaris, 

 Cataphractus, and Leptorhynchus, but also on the lingual papillae of 

 Cymnoplax cegyptiacus, and in the pouch of Pelicanus and Onochrotalus. 

 In external appearance it has a general resemblance to Branchiohdella. 

 Attached to the very delicate rectum are four pairs of very sinuous 



* Stud. Biol. Lab. JohnsrHopking Univ., iii. (1884) pp. 1-27 (2 pis.). Cf. this 

 Journal, ante, p. 226. 



t Ann. Sci. Nat. (Zool.), xvi. (1884) 18 pp. (3 pis.). 

 % Comptes Eendus, xcviii. (1884) pp. 1597-1600, 



