o/Carterella Lititeuta, Fotts. 393 



position of SjJongtUa in the animal series more clear than it is 

 at present*. 



But, in alluding to specific difierences in the species which 

 do bear the cirrous ap})endages and those which do not, I can 

 Old J saj that the spiculation of the statoblasts of Hetero- 

 meyenia repens (about which Mr. Potts himself seemed to have 

 some doubt; as the label on his slide also bears " ? Meyenia 

 Baileyi ") and those of Carterella tuhisperma appears to me 

 to present hardly more than '' varieties " of Spo ng ilia Bailey ij 

 Bk. (Proc, Zool. Soc. 1863, p. 13, pi. xxxviii. fig. 6), of 

 which unfortunately neither Mr. Potts nor myself possess a " 

 type specimen, so that we liave nothing to fall back upon in 

 this respect but Dr. Bowerbank's description and illustration, 

 Avherein at page 13 he observes that the birotulate spicule is 

 " four or five times as long" as that of Sponyillajluviatilisj 

 which corresponds with the representations [op. et I. c. figs. 1, b 

 and 6, h), both of which are drawn to the same scale, viz. 

 " X 660." But, to be sure of the actual measurements of the 

 bivotulates in Spjongilla Baileyi^ Bk., 1 applied for this to Mr. 

 Stuart O. Ridley, F.L.S., who has charge of Dr. Bowerbank's 

 typ)e specimens now in the British Museum ; and, in reply, he 

 states that the birotulate spicules on the slide range from " 93- 

 25000thstol47-25000ths inch " in total length, thus evidencing 

 a heterogeneous mixture of long and short spicules, in this 

 respect similar to what is characteristic oi lleteromeyenia repens^ 

 but in the matter of length more nearly allied to the biro- 

 tulates in Heteromeyenia aryyrosperma, which, according to 

 Mr. Potts's mounted specimen, range from l-333rd to l-146th 

 inch, where the maximum is still greater than that of >S'. Baileyi. 

 This heterogeneous mixture in length of the birotulates around 

 the statoblast I observe to be the case in all three species of 

 Carterella^ but more so in C. tuhisperma and G. latitenta than 

 in C. tenosperma, where they are not only much shorter and 

 much more equal in length, but so different in shape as to 

 justify specific distinction. 



lieturning to the cirrous appendages, the tubular prolongation 

 in the species which comes from Bufialo, viz. Carterella tuhi- 



* The little mass of statoblasts of Pectinatella magnifica from the 

 Schuylkill river, Pennsylvauia, -which reached me in an equally smaU 

 test-tube with water on the 9th November, 1881, beg'an to germinate 

 towards the end of February 1882, in well-water, occasionally changed 

 during the interval. It was then transferred to a small freshwater aqua- 

 rium (glass bowl) with Anacharis ulmiasfrum, where it continued to 

 germinate freely up to the 8th April, when it gradually disappeared 

 (i^ died out). Many of the statoblasts were entirely a\ ithout cirri, although 

 each opened like the rest, in the line of suture (after the manner of an 

 oyster), and gave issue to a tinely developed Pecthta fella. 



