Dr. Bowerbank on certain Hpecies of Sponges. 489 



Leuconia glomerosa, Dr. Gray says, " is the same as the 

 species I long ago described and figured under the name 

 of Apkroceras alcicornis (P. Z. S. 1858, p. 113, t. x.)." I 

 can only say that I have carefully examined at the British 

 Museum the specimen presented by Dr. Harland, and its 

 structure is specifically distinct from my L. glomerosa. In 

 truth, any one looking at the figures of the two would at once 

 come to the conclusion that they were different species. 



Ciocalypta Tyleri. — I am certainly astonished that Mr. 

 Carter and Dr. Gray cannot see the remarkable anatomical 

 differences in structure of the genera Halichondria and Cio- 

 calypta. I can only refer them to the ' Philosophical Trans- 

 actions ' for 1862 (for Ciocalypta^ page 1195, tab. xxiii. figs. 

 4&5, and for Halichondria to page 1113, tab. xxxiii. figs. 

 1 & 5) to disabuse them of their very hasty and inaccurate 

 conclusions. 



As I have given my reasons, in the third volume of the 

 '■ Monograph of British Spongiadse,' for disagreeing with my 

 friend Mr. Norman in not adopting his genus Oceanapia^ I 

 shall not trouble Dr. Gray on that subject. 



Dr. Gray writes in page 267 as follows : — " Mr. Carter 

 informs me that the Haliphysema tubulatum (P. Z. S. 1873, 

 p. 29, t. vii.) is a massive form of Ins Dictyocylindrus of the 

 British coast." In this short sentence there are two errors. 

 In the first place, the skeleton-structure of Haliphysema 

 tubulatum is a series of hollow membranous tubes, and the 

 structure of Dictyocylindrus is essentially that of a solid 

 cylinder composed of closely compacted spicula. In the next 

 place, the genus Dictyocylindrus was established by me, not 

 by Mr. Carter (see ^ Philosophical Transactions of the Royal 

 Society' for 1862, p. 1108). j\Ir. Carter can scarcely be 

 obliged to Dr. Gray for such palpable misstatements. 



Spongionella Holdsworthii. — Dr. Gray's style of treating 

 his brethren in the study of natural history is very off-handed 

 and magisterial. In treating of this sponge (p. 266) he writes : — 

 " This sponge has been formed into a genus under the name of 

 Fhjllospongia. It has very little affinity and quite a dif- 

 ferent structure to Spongionella pulchra, which is considered the 

 type of the genus." Here, again. Dr. Gray is, as usual, very- 

 inaccurate. In the first place, there is no such species as 

 Spongionella pulchra as the type of the genus : the type spe- 

 cimen of the genus is in my possession, and its specific name 

 is not pulchra but pidchella ; and its structural peculiarities and 

 the mode of the an-angement of its skeleton are in perfect accord- 

 ance with the corresponding organs of S. Holdsioorthii, as 

 any one may perceive by comparing the skeleton figure of 



