896 SUMMAET OF CrKEEXT LESEARCHE? EELATrNG TO 



and illustrated by 45 plates. The author discusses in some detail the 

 question of the determination of the " axis " of the Echinoidea, and 

 compares the coronal plates of the test. After a chapter on acanthology, 

 the author insists on the hopeless nature of the attempt to represent 

 the direct succession, either diagrammatic-ally or descriptively, of the 

 Echinids of the present epoch fi'om those of the chalk. The Jurassic, 

 cretaceous, and tertiary Echinoids are considered in relation to the 

 present Echinid fauna'; and from this the work passes to the more 

 strictly descxiptive portion, to conclude vrith systematic tables, which 

 contain an account of the horizontal and vertical distribution of the 

 Echinoidea. 



Morphology of the S or- Anal Plate.* — In describing a case of 

 the apparent retention of this plate by a young Echinometra, Prof. 

 Jeffrey Bell takes occasion to raise the question whether this plate 

 has " of itseK or primarily, any relations to the covering plates of the 

 anal area"; in the present specimen no such relations are to be 

 seen, and in it, just as in Salenia, there is no question as to the small 

 anal plates being distinct from the sur-anal. It is now generally 

 supposed that the sur-anal plate and the large plate found among the 

 covering plates of the anal area of some forms, are homologous, but 

 the author points out that this latter lies within the boundary of the 

 anal area, and he concludes that so far as morphological identity can 

 be spoken to by similarity in position, this homology must be some- 

 thing more than doubtful ; the large anal plate of the Temnopleuridee 

 has probably been secondarily acquired. 



ComatTilae of th.e Leyden Museum.t — ]\Ir. P. H. Carpenter has 

 been able to do good service to the students of th.is group by the 

 publication of these notes, as the Leyden Museum contains the 

 types of six of the species described by J. Miiller ; a key is given 

 to the species here described, the old forms being fully commented 

 on. as well as eleven new species described. These are A7it€don 

 pers'pinosa. pinniformis, serripinna, himaculata, hreticuneata, Itemcirra, 

 and spicata : Adinometra rohvMipinna. alternans, schlegeli. smi peronii. 

 Xearlv all these forms are from the Eastern seas. A discussion of 

 the characters of the Phanogenia typAca of Loven is entered into, and 

 that, for a time, difficult form is now placed in the genus Adinometra. 



Ccelenterata. 



Shortened Development in the Discomednsae.i — Professor E. 

 Haeckel has lately had a very favourable opportunity of studying that 

 well-known member of this group, Aurelia aurita, having kept a 

 number of specimens in his aquarium. He has observed certain 

 phenomena in the mode of reproduction which deviate from those 

 which usually occur. The normal process of reproduction is that 

 which prevails in the group generally, viz. by ovum, gastrula, 

 Scyphistoma, metamerically segmented or Strobila-stage, culminating 



* Jonrn. Linn. Soc. (Zool.), xv. (18S1) pp. 318-20. 



t Xotes from the Leyden Muaeum, iii. (1881) pp. 173-217. 



% 'Metagenesis und Hvpogenesis von Aurelia aurita' Jena, 1881, 4to (2 pis.). 



