1000 SUMMARY OK CURRENT RESEARCHES RELATING TO 



same differentiation of tho (six) mesenteries ; and there is distinet 

 dimorphism. Differentiation of functions is, however, incomplete, 

 for both forms are reproductive, and hoth, apparently, digestive. In 

 M. aspera there is an absence of dimorphism ; this difference is very 

 remarkable, but in face of the great antiquity of these forms, the 

 similar structure of the colony in both, and the fact that they exhibit 

 a similar differentiation of the mesenteries, it is not to be inferred 

 that their systematic relations are unsound. 



In preparing microscopic sections the method of v. Kocli was 

 found to be extremely useful. 



Ctenophora.* — Prof. C. Glaus notes the occurrence in the Adriatic 

 of the beautiful Deiopea lcaloldenota. He corrects and amplifies Chun's 

 description, though it is possible that the form examined was a 

 different species. After a description of this form, Prof. Claus passes 

 to a discussion of the architecture of the Ctenophore body. He 

 criticizes the conclusions and terminology of Hackel, Chun, and others, 

 and proposes certain improvements. It is not, however, profitable to 

 attempt a summary of a promorphological discussion. 



Porifera. 



Development of Sponges. f — Prof. A. Gotte has some notes on 

 Dr. Heider's late paper on the metamorphosis of Oscar ella lobularis, 

 in which he allows that some of his generalizations must now be 

 regarded as true of some forms only ; he cannot, however, allow the 

 correctness of Heider's supposition that the gastrulaa and their 

 germinal layers are always the homologues of those of other poly- 

 plastids. 



New Tetractinellid Sponge with radial structure. $ — Dr. W. 

 Lampe gives an account of a new sponge, Tetilla japonica, which 

 exhibits a radial symmetry. In form the sponge is ellipsoidal at the 

 oral end, and exactly in the longitudinal axis there is a single circular 

 oral opening ; at the aboral pole the sponge gradually diminishes in 

 breadth ; the surface is beset by a number of small conical processes, 

 among which are small infundibula, at the base of each of which there 

 is a dermal pore ; the edges of the pores are elongated by the palisade- 

 like spicules which project around them. 



The author gives a full account of the skeleton, and directs atten- 

 tion to the remarkable radiate and symmetrical structure of the water- 

 canal system ; the mouth leads into a cavity which widens out below, 

 and is always continued into six vascular trunks which take an 

 aboral direction ; these divide the sponge into an internal core and 

 an external mantle. A multiramified system of tubes traverses 

 the soft parts of the sponge at right angles to the radial canals ; when 

 their maze is comprehended it appears that there are antagonistic 

 systems of canals. The dermal pores are constant and are never 



* Arbeit. Zool. Inst. Univ. Wien (Claus), vii. (1886) pp. 8o-96 (1 pi.). 



t Zool. Anzeig., ix. (1886) pp. 292-5. 



X Arch. f. Naturgesch., lii. (1886) pp. 1-18 (1 pi.). 



