424 NOTES AND MEMORANDA. 



between the circulatory and the respiratory organs in the Arthropoda. 

 He finds that in Insecta, Myriapoda, and Arachnida there are as 

 many pairs of clefts in the dorsal vessel as there are pairs of stigmata; 

 that in the Crustacea there are, likewise, as many clefts as there are 

 pairs of branchias ; this obtains when the gills are set on the abdomen 

 and post-abdomen ; when, however, the gills are gathered under the 

 cephalo-thorax, then there are in the heart as many pairs of clefts as 

 there are pairs of gills under the shelter of this investment. 



New Branehiopoda off the French Coasts.— M. Hesse describes* 

 some new Crustacea, for which he forms a new genus — Copechoites 

 {kwttt], oar, x'^^'^Vi lifiii") '•> f-s their relation to other forms will probably 

 be of interest to naturalists, we append his table of classification, 

 which, as he says, is based on that of Norman and Brady : — 



Legion : Branehiopoda. 

 Sub-order : Cladocera. 

 Division: Calyptomera. 

 Tribe : Anomopoda. 



Family — CopechcBtidce . . . . Copechoete, Hesse. 



„ Bosminidoe Bosmina, Baird. 



„ MacrotrichidcB .. .. Macrothrix, Baird, &c. &c. 



„ Lynceida; Lynccus, Miiller, &c. &c. 



Four new species, to which the names elongata, affinis, fissa, and 

 armoricana are given, are described and figured ; they are all of 

 extremely small size, and are marine in habitat. No details can be 

 given as to the history of their development, but eggs were found, 

 which in some cases were strong and greatly elongated, and in others 

 spherical ; in the former case the enveloping membrane was thick, 

 and the thinness of this investment in the latter case appeared to be 

 due to its earlier condition of development. The detailed description 

 which is given indicates the affinities of these forms to the Bosminidce. 



As single specimens — which, by the way, all belonged to females — 

 were alone found, M. Hesse is unable to give any anatomical details ; 

 he states, however, that the antennte were long and delicate, but that 

 of these appendages only one pair was to be observed ; as to the other, 

 no definite statement is possible ; the abdominal is much shorter than 

 the post-abdominal region ; this latter, or tail, has a truncated termi- 

 nation, which is very large and surrounded by a horseshoe-shaped 

 pad ; it is provided with two powerful muscles, which must evidently 

 be of great assistance in locomotion. The branchiaa, which are elon- 

 gated, are set towards the centre of the body ; the enteric tube takes a 

 direct course from before backwards. The eyes are seated on short 

 broad peduncles, and can be moved laterally or in a line parallel to 

 the long axis of the body. 



They were observed to live 283 millimetres below the surface of 

 the water, at which level they were probably supported by the air 

 entangled in the valves of their shells ; as in the Bosminid(P, the shells 

 of the Copech(Btidce form a hood-like protection for the anterior 

 portion of the head, but they are at once distinguished by the different 



* 'Ann. Sci. Nat. (Zool.),' vii. (1878), Nos. 5-G. 



