ZOOLOGY- AND BOTANY. MICROSCOPY, ETC. 59 



planes parallel to the first equatorial plane. Thirty-two cells are thus 

 established, but Soulier explains how it is that, as a matter of fact, there 

 are thirty- four, 



Echinoderma. 



Multiplication by Fission in Holothurians.* — W. J. Crozier 

 observed nine cases in which Holothuria surinamensis divided itself 

 into two parts. The animals concerned seemed healthy, and bore no 

 visible signs of having been in any way injured. In no case did the 

 halves divide again, although in two cases the resulting portions lived in 

 the laboratory for a month, during which time, even in the absence of 

 food, missing" parts were regenerated. In one case the division occupied 

 five days ; in another, twenty-four hours. It begins midway in the 

 body with a deep insinking of the dorsal bivium. A powerful circular 

 ■constriction, accompanied by some local disintegration of the integument, 

 completes the separation. During the progress of division the animal is 

 quiescent, although it may be adhering firmly by its tube feet to the 

 vertical wall of the aquarium. When the constriction and separation of 

 the skin and muscle-layers is completed, a short length of intestine 

 usually remains for a time connecting the two pieces ; it may rupture 

 <;lose to one of them, or may disintegrate completely. The resultants of 

 the division do not move apart, but remain quiescent. Many regenerat- 

 ing specimens were observed. There is thus good reason to believe 

 that Holothuria surinamensis in the adult state normally multiplies by a 

 process of binary fission. 



Buccal Armature of Conulus.f — Herbert L. Hawkins describes the 

 buccal plates and girdle of Oonuhis albogaUrus, an Echinoid from the 

 Upper Chalk. The perignathic girdle is very like that of Discoides, with 

 modifications due to the greater degree of thickening of the inter-radial 

 coronal plates and to the massive character of the buccal plates. The 

 existence of a lantern is inferred, the arguments being based upon the 

 known characters of the girdle, and upon analogy with related types. 

 Certain imperfect ossicles within the test of a small specimen are 

 considered to represent portions of the lantern. 



Coelentera. 



Australian Alcyonarians.|— Hjalmar Broch reports on a collection 

 of Alcvonarians made bv E. Mjoberg's Swedish Scientitic Expeditions to 

 Australia (1910-13). There were ~' twenty-five species, fourteen new. 

 The representation of the different families is curious, ))ut finds its 

 -explanation in the bathvmetrical conditions of the locality (a pearl-bank 

 west-south-west of Cape Jaubert) where the collection was made. Of 

 considerable interest was the following ■.—NephthyigorgialdlkenthaU^^. n., 

 StmlerioUs crassa, Suberiopsis australis g. et sp. n. (near Anthothelii), 

 Titanideum mjohergi sp. n., and Alertigorgia orientalis (Ridley). 



• Amer. Nat., li. (1917) pp. 560-6 (2 figs.). 



+ Geolog. Mag.,iv. (1917) pp. 433-41 (1 pi.). 



: K. Svensk. Vetensk. Handliugar, lii. (1916) pp. 1-48 (4 pis. and 62 figs.). 



