258 



SUMMARY OF CUERENT RESEARCHES RELATING TO 



(From this it will be seen that the length may vary from 0"168 to 

 • 243 mm,, the maximum diameter from • 009 to • 024, and that there 

 is some approximation to an inverse proportion between the length 

 and the breadth.) Four varieties of the sponge are found ; the skeleton 

 spicules of the first {var. a) are more thickly spined at the ends than 

 in the middle ; var. /3 has the middle of the spicule devoid of spines, 

 and the spicule is thicker ; var. y has its spicules still thicker, but 

 spined only at the extreme ends ; in var. 8 they agree with those of the 

 preceding foiTQ but are smaller. Their chief proportions in the four 

 varieties are instructive : — 



Length 



Maximum diameter . . 

 Diameter just before'l 

 end / 



Var. $. 



Tar. y. 



■18 to 

 •012 „ 



•006 



231 

 015 



•198 to 

 •018 „ 



•006 „ 



231 

 024 



•270 to 

 •015 „ 



339 

 03 



Var. 5. 



•165 to 

 •015 „ 



•009 -006 „ •oi5j •ooe 



•219 

 •024 



•009 



L. hacillifera is the first new species ; it is found in shallow water 

 on the south-west side of the lake. It differs from baicalensis in its 

 irregular flattened form, in the slender proportions of the perpen- 

 dicular fibres, which contain only four to six spicules in their thick- 

 ness, and the skeleton spicules are bacillar and spined and vary in 

 length from • 225 to • 27 mm. and in thickness from • 021 to • 027. 

 There are three varieties, diifering more or less in the form and 

 proportions of the oscula and spicules, 



L. intermedia is also a flat encrusting form ; it presents characters , 

 of transition to Spongilla. The horny substance is but slightly 

 developed ; the skeleton spicules are bacillar, with abruptly pointed 

 ends and covered with spines which are most abuudant at the ends ; 

 they vary in length from 0*162 to 0*222 mm. and in diameter from 

 0*012 to 0-024 mm.; in the varieties they are somewhat longer and 

 generally thinner. 



L. papyracea is encrusting, but very thin ; it has no vertical 

 skeleton-fibres; the skeleton spicules are bent and bacillar, with rounded 

 ends, and spined all over ; the horny substance is delicate ; the skeleton 

 spicules vary in length from * 12 to * 144 mm., and in diameter from 

 •012 to -021 mm. 



With regard to the aggregation of sponge-forms from very widely 

 separate localities united by Miklucho-Maclay under the name Veluspa 

 polymorpha, Professor Dybowsky comes to the conclusion that two of 

 these so-called varieties are species distinct from the rest, and 

 belonging, the var. gracilis to the genus Reniera, the var, ardica to 

 Pachychalina (being identical with P. compressa Schmidt) ; a third 

 variety [baicalensis) is based on Spongia baicalensis Pallas, assigned 

 above to Lubomirskia ; the remaining eight varieties of Miklucho- 

 Maclay are now grouped under the single generic and specific 

 designation, Veluspa polyraorpha. Veluspa, as freshly characterized, 

 is shown to be allied to Clathria Schmidt, and Trachya Carter. With 

 Clalhria it agrees in the peculiar form and the two sizes of its 



