76 SUMMARY OF CURRENT RESEARCHES RELATING TO 



together ; their characteristic entire margins are gone, the rotulcs 

 being represented merely by a line of very fine rays. 



Australian Sponges.* — II. v. Lendenfekl's monograph of the 

 Australian sponges is founded iii)on specimens collected by the author, 

 and those belonging to the museums of Christchurch and Duuediu, 

 New Zealand, and of Adelaide, South Australia. Tlie paper is pre- 

 ceded by a summary of our knowledge of the sponges (with 178 biblio- 

 graphical references) divided into four periods, the first from Aristotle 

 to Belon, 350 b.c. to 1553 a.d., the second from Belon to Grant, 1553 to 

 1826, the third from Grant to F. E. Schulze, 182G to 1875, and the 

 fourth from Schulze to the present day. 



This is followed by a general outline of the anatomy, minute 

 structure, embryology, and physiology of the sponges, with remarks 

 on their systematic position and classification. The aiithor's classifi- 

 cation differs somewhat from that c;f recent authors, and is arranged 

 so as to suit the Australian as well as the European species. The 

 sponges are considered as Metazoa, forming a class of the Cceleuterata, 

 and divided into six orders : — (1) Calcispongise (calcareous skeleton) ; 

 (2) Myxosjiongife (no skeleton or with only few and scattered siliceous 

 bodies ; (3) Ceraos2)ongice (skeleton comiwsed of horny fibre, which 

 may contain foreign bodies, but never proper spicules. Siliceous 

 bodies rarely developed as small scattered spicules in the ground sub- 

 stance) ; (4) Monacticera) (skeleton composed of anastomosing horny 

 fibres within which there are monoaxial spicules. Sometimes with 

 flesh-s[>icules) ; (5) Hyalospongiae (skeleton composed of siliceous 

 spicules which have originally been formed as flesh-spicules and 

 afterwards may coalesce to form hard skeletons) ; (6) Monactibyalfe 

 (with a skeleton composed of biacerate or truncate spicules which 

 may coalesce slightly, and which have originally been formed as 

 flesh-spicules). 



Wide Distribution of some American Sponges.f — E. Potts refers 

 to the wide distribution of some North American fresh-water sponges, 

 more especially SpongiUa fragilis, which may be regarded as ranging 

 throughout the American Continent ; it has also quite recently been 

 found in Russia. Amongst a number of specimens from Nova Scotia 

 the author met with Meyenia Everetti, Mills, this being only the second 

 instance in which the species has been discovered. In this specimen 

 the birotulate spicules average one-third longer than those before 

 examined, and are in every way more robust ; thus confirming a rule 

 long since observed by the author, that spicules of all species increase 

 regularly in size and solidity as we descend from high altitudes 

 towards the sea-level, where is found the extreme limit of the series. 

 He does not attribute this gradation to a change of climatic conditions, 

 but more jirobably to a gradual and constant improvement in the food 

 supply or in the siliceous constituents of the water. The author 

 instances species in which the working of this rule has been observed. 



* Proc. Linn. Soc. N. S. Wales, ix. (1S84) pp. 121-54, 310-44. See also the 

 remarks on the author's paper on the Australian Monactmellida, this Journal, iv. 

 (1884') p. 394. 



t Proc. Acad. Nat. Sci, Philad., 1884, pp. 215-7. 



