ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 641 



very definite concretions, but in no case could any sign of a concretion 

 be detected within or between tlie cells. The presence of these 

 bodies, which are extremely minute, may be associated with the pro- 

 cess of ecdysis ; phosphoric acid was found in them, whereas Nibeski 

 found carbonate of lime in Orchestia cavimana. We must wait for a 

 knowledge of their developmental history before we can say definitely 

 whether or no they are homologous with the Malpighian tubes of the 

 Tracheata. 



Development of the Egg and Formation of the Primitive 

 Layers in Cuma Rathkii.* — Dr. H. Blanc's researches on this 

 subject, of which mention has already been made,"]" are now published 

 in extenso. 



Development of Cyclops. + — The development of Cyclops has been 

 studied by a great many authors, but little is known concerning the 

 origin of the body-cavity and most of the internal organs. M. F. 

 Urbanovics has addressed himself to solve these questions, and has 

 arrived at the following results : — 



A dorsal organ is formed as in the Isopoda, which is composed of 

 a single layer of cylindrical cells. The body-cavity is formed by 

 paired excavations of a mesoblast band ; each pair of cavities corre- 

 s^jonds to a segment and the dissepiments dividing them from each 

 other only disappear very late ; the dorsal and ventral mesenteries 

 persist throughout life ; the dorsal mesentery contains a space which 

 is a remnant of the blastocoel and plays an important part in the 

 circulation in the absence of a heart. It is obvious that these facts 

 indicate a far closer similarity with the Tracheata and Annelida than 

 is admitted by Balfour in his ' Comparative Embryology.' 



Anatomy of the Cirripedia.§ — Dr. P. P. C. Hoek has issued a 

 supplementary memoir on the Cirripedes of the " Challenger," which, 

 as we have already stated, \\ he promised to prepare. 



The complementary male of Scalpellum ha^ never been described 

 since the time of Darwin's first notice of it ; Dr. Hoek found this 

 male in 19 out of 41 new species, and always at about the same 

 place, that is, a little above the musculus adductor scutorum ; in 18 

 of the species the testes were mature ; in thirteen cases the male was 

 more degenerated than in S. vuhjare. The 24 forms whose males 

 are now known have either a special capitulum and a stalk, as in 

 three species ; or there is no division of the body, but there are rudi- 

 mentary shell-valves, as in eight species ; or there is no division of 

 the body and no valves, as in thirteen species. The first of these are 

 littoral in habitat ; the second live at depths of at least 700 fathoms ; 

 and the third (with three exceptions) live at depths greater than 1000 

 fathoms. Two of the three exceptions belong to the arctic fauna, 

 where, as is now well known, deep-sea forms of other latitudes are 

 found living at lesser depths. 



• Rec. Zool. Suisse, ii. (188.5) pp. 2.'i3-75 (1 pi.). 



t Hee this Journal, and;, p. 2'^H. 



X Z'xA. AiiZfit,'., vii. (1884) pp- 015-9, 



<j TijdHchr. Ncdorl. Dierk. Vorcon., vi. (1882-.0) pp. 64-142 (G pis.). 



II Sfte tbi« Jounifil, iv. (1H84) p. 891. 



