202 LIVERPOOL BIOLOGICAL SOCIETY. 
arranged in about five longitudinal parallel rows. These 
fibres seem to consist only of connective tissue and spi- 
cules. Ceratose does not appear to be present in them. 
Esperella floreum, Bowerbank. 
Hymeniacidon florewm, Bowerbank (vol. ii., p. 190). 
Rhaphiodesma florewm, Bowerbank (vol. ili., p. 94). 
This species is an addition to our fauna, and was dredged 
off the Calf of Man, on the ‘“‘ Hyena’”’ cruise of Haster, 
1889. Another species of the same genus, Hsperella ega- 
gropila, J., had previously been collected at Holyhead.* 
Our species was first described by Bowerbank, under the 
name Hymeniacidon floreum, which was afterwards changed 
by the same author into Rhaphiodesma floreum. Oscar 
Schmidt + was the first who pointed out that this species, 
together with Hymeniacidon lingua and Hymeniacidon sub- 
clavata belonged to Nardo’s older genus Hsperia. In the 
course of time the genus Lsperia had to be changed into 
Lisperella,t so that we now arrive at the name Hsperella 
floreum, B. ' 
Our specimen was found encrusting a living Pecten oper- 
cularis, with a thin and rugged layer of greyish colour. 
The thickness of this layer is about 1mm. The skeleton 
consists of megascleres and microscleres. The former are 
styl (0°24 mm. by 0:008 mm.), which le in irregularly 
arranged and loose bundles. The microscleres consist 
firstly of anisochele, which are arranged in beautiful - 
rosettes. Similar structures are found in Hsperella linjua, 
B.,§ in Jophon abnormalis, Ridley and Dendy,|| and in 
* Thos. Higgin, ‘‘ Report on the Porifera of the L.M.B.C. District.” In 
** Fauna of Liverpool Bay,” vol. i., p. 85. 
+ Oscar Schmidt, ‘‘ Spongienfauna des Atlantischen Gebietes,” 1870, p. 76. 
+ Vosmaer, ‘‘ Bronn’s Klassen u. Ordn. d. Thierreichs, Porifera,” p, 353. 
§ Bowerbank, ‘‘ British Spongiadee,” vol. i., pl. xviil., fig. 297. 
|| Ridley and Dendy, ‘‘ Report on the Monaxonida, collected by H. M, § 
Challenger,” pl. xvii., fig. 7. 
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