82 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Porifera. 



Australian Homocoela and the Homodermidse.* — Dr. E. v. Len- 

 denfeld, recognizing that the sponge-natnre of the Physemarina is 

 not sufficiently proved, regards the Asconidee as the simplest of all 

 sponges. They form the first family of Polejaeflf's suborder Homocoela, 

 in which there is no differentiation of the endodermal epithelium. "j" 

 The second family is a new one, and is called Homodermidse, the 

 new genus Homoderma combining the characters of the Syconidse with 

 those of the Asconidae ; the inner surface is complicated, so as to form 

 radial sack- shaped excrescences similar to the radial tubes of the 

 Syconidge. The two sponges Ascaltis canariensis and A. lamarchii, 

 described by Prof. Hackel, have a similar structure of the body-wall. 

 The author gives a detailed description of H. sycandra, together with 

 some notes on its postembryonal development or metamorphosis ; at 

 first its inner surface is perfectly simple, and chambers appear as the 

 sponge grows ; when adult, it is 2 mm. high, and has been found at 

 Port Phillip, Victoria. 



Spongilla fragilis.J — Herr Frant Petr describes the anatomy of 

 a Sjjongilla fragilis (Leidy) found in Bohemia, and compares it with 

 that of other forms. He maintains the identity of the characteristic 

 air-chamber envelope of the gemmulse with the parenchyma sheath of 

 Euspongilla and EpTiydatia species, and regards its occurrence as 

 probably constant in all fresh-water sponges. 



Fresh-water Sponges from Mexico. § — Mr. E. Potts describes a 

 new variety (Palmeri) of Carter's sponge Meyenia plumosa. It has 

 the same general characters and the various spicules seen in the 

 type : it was found on the banks of the Colorado river : the only other 

 locality is Bombay, where Carter's specimen was found. The lower 

 reaches of the Colorado are exceedingly hot and dry, and the chief 

 vegetation consists in cacti, &c., and Stromhocarpus puhescens ; on the 

 branches of the latter the sponge is found, and since the floods are 

 only out about six weeks in the year, the sponge must be dry for the 

 rest of the year. Reproduction can only take place during the wet 

 season. This variety differs from Carter's in the presence of com- 

 plicated sabdermal spicules. 



Vosmaer's Sponges. || — Parts 8-11 of Dr. G. C. J. Vosmaer's 

 ' Porifera ' have been published, with plates 19-25. 



The account of earlier classifications is continued, that of Dr. 

 Gray being first taken up. The Porifera are defined as : " Very 

 variable in form, different between the limits of one single species. 

 The body consists principally of a connective-tissue-like substance, 



* Proc. Linn. Soc. N.S. Wales, ix. (1885) pp. 896-907. 



t The awkward wording of a sentence on p. 1014 of vol. v. of this Journal 

 causes the non-diflferentiated character of the endoderm to be ascribed to the 

 Heterocoela instead of the Homocoela. 



X SB. K. Bohm. Gesellsch. Wiss., 1885, pp. 99-111. 



I Proc. U.S. Nation. Mus., viii. (1885) pp. 587-9 (1 fig.). 



II Bronn's ' Klassen u. Ordnungen d. Thierreiches,' 8vo, Leipzig and Heidel- 

 berg, 1885. 



