ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 191 



Porifera. 



Red Sea Sponges.* — R. W. Harold Row reports on a large collection 

 of non-calcareous sponges made by Cyril Crossland in coastal waters in 

 the Sudanese Red |Sea. Besides two species of Halisarca, there are 49 

 species of Tetraxonia, of which 24 are new ; and 26 species of Euceratosa, 

 of which 7 are new. Among the new Tetraxonia there are two new 

 genera — Diastra (an Epipolasid with spherasters of two kinds, one a 

 minute dermal spheraster, and the other, large and simulating a ster- 

 raster ; with the main skeleton consisting almost entirely of a cortical 

 layer of tangentially placed oxea) : and Anacantheea (a Heteroxyin, in 

 which the oxea are not differentiated into two forms and have no spines ; 

 there are microscleres). Among the new Euceratosa there are two new 

 genera — Euryspongia, with a Spongelid canal-system and europylous 

 chambers, but with a skeleton exactly similar to that of Euspongia 

 irregularis, and Duriella, nearly allied to Heteronema, Imt with a much 

 less regular skeleton. 



Of the 98 species of sponges obtained by Crossland altogether, 79 are 

 new to the Red Sea, and the list has been raised to 187 species. There 

 is a very considerable affinity with other parts of the Indian Ocean, 49 

 species being common to some part of the two regions. Three species 

 common in the Mediterranean are now found also in the Red Sea, viz. 

 Leucandra aspera, Plarortis simplex, and Euspongia zimocia. They have 

 probably migrated. 



Protozoa. 



Gastrsead Foraminifera.t — Alexander Schepotieff discusses the seven 

 alleged species of HaUphysema, and thinks that all may be referred to 

 H. tumanowiczii. He has also studied Gastrophysema, which has only 

 been seen twice before — a 2-chanibered form {G. cUtluilmniwn), by 

 Haeckel, and a 4-chambered form {G. scopiila), by Carter. 



A detailed description is given of HaUphysema and its alternation of 

 generations. 1. A gamont stage is represented by a mononuclear form 

 with a long tine stalk and by branched multinuclear colonies which arise 

 by incomplete gemmation. 2. Gamogeny includes the formation of 

 cysts, of microgametes, and of macrogametes, and the conjugation of 

 the anisogametes to form a mononuclear zygote (the mononuclear Plas- 

 modium or amoeba of the first generation). 3. The agamont stage is 

 first mononuclear, then multinuclear, and has a short broad stalk. 4. 

 Agamogeny includes the formation of naked mononuclear agametes 

 (amoebai of the second generation) and the change of these into shelled 

 gamonts. 



It is probable that there is an alternation of generations in Gastro- 

 physema, and the author describes mononuclear stages, multinuclear 

 stages, and shells with cysts. 



Disintegration of an Infusorian.J — G. W. Corner describes the 

 disintegration of an entrapped ^'orticellid, a species of Cothurnia. It 

 wriggled frantically for hours, slowed down, became spherical and 



* Journ. Linn. Soc. (Zool.) xxxi. (1911) pp. 287-400 (7 pis. and 26 figs.). 



t Zool. Jahrb., xxxii. (1911) pp. 43-76 (2 pis.). 



X Johns Hopkins Univ. Ciic, 1911, No. 2, pp. 55-8 (4 figs.). 



