l.~»0 SUMMARY OF CURRENT RESEARCHES RELATING TO 



15 and 6] in males. In G. normani the gonadial tubes vary from about 

 250 to more than 800, and the three males examined Lad more than the 

 three females. The calcareous collars of the two species mentioned are 

 carefully compared, as also the differences in the spicules of the tube- 

 feet. The growth-stages of the bell-shaped spicules of 0. normani are 

 described. 



It was found that in the species normani, hyndmanni, elongata, the 

 gonad consists of numerous short cylindrical tubes, and the dorsal as well 

 as ventral ambulacra have well-developed tube-feet. In the species 

 saxkola and brunnea, the gonad consists of relatively few large club- 

 shaped tubes, and the dorsal ambulacra contain mostly ambulatory 

 papillae (less numerous than the tube-feet in the ventral rows), but have 

 a few definite tube-feet at the anterior ends. The species of this second 

 group may have to be referred to the genus Colochirus. The author has 

 also notes on Cucumaria elongata and Thyone raphanys from the 

 Plymouth district. 



Ccelentera. 



Development of Plumularian Planula.* — Ernest Warren describes 

 a Plumularian, provisionally called Schizotricha simplex sp. n., and the 

 development of its planula. The hydroid, collected at the mouth of 

 the St. John's River, Pondoland, shows the typical characters of the 

 genus Plumularia, with the exception of the presence of downward 

 directed offshoots from the pinnae, and the somewhat unusual occurrence 

 of the main stem bearing hydrothecae. The pinnules are similar in every 

 way to the pinnae, and they originate from the pinnae just as the latter 

 do from the main stem. They bear a short basal internode with trans- 

 verse nodes and no nematophore. 



The development of the planula is noteworthy in that the egg never 

 becomes charged with yolk. The ovum remains small and segments in 

 the midst of a feeding or placental tissue. Ultimately the embryo 

 grows into a well-developed planula, with dimensions very greatly ex- 

 ceeding those of the original egg. The placental tissue arises as a 

 modification of a specialized portion of the ectoderm of the blastostyle. 

 This portion forms a kind of cap over the young ovum, and may be 

 regarded as representing the manubrial ectoderm of a rudimentary 

 gonophore which bears one egg. 



Remarkable Longitudinal Scissiparity in a Madrepore.f — Ch. J. 

 Gravier describes in Schizocyathus fissilis Pourtales a remarkable mode 

 of asexual multiplication. The calyx is always inserted obliquely on a 

 narrow base, triangular in cross section. There are three cycles of 

 septa, and there is no columella. Six groups are formed, each consisting 

 of a median septum of the first cycle and two lateral septa of the third 

 cycle. Pourtales interpreted the facts as due to intracalycinal budding. 

 Lindstrom suggested that there was a dislocation into six groups, that 



* Arm. Natal Museum, iii. (1914) pp. 83-102 (1 pi. and 4 figs.). 

 t Comptes Rendus, clx. (1915) pp. 103-5. 



