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 fioreu7n, Bowerbank (vol. ii., p. 190). 

 Rhaphiodesma jioreum, Bowerbank (vol. iii., p. 94). 



This species is an addition to our fauna, and was dredged 

 off the Calf of Man, on the " Hyaena" cruise of Easter, 

 1889. Another species of the same genus, Esperella cega- 

 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 Bhaphiodesma floreum. Oscar 

 Schmidt f was the first who pointed out that this species, 

 together with Hymeniacidon lingua and Hymeniacidon suh- 

 clavata belonged to Nardo's older genus Esperia. In the 

 course of time the genus Esperia had to be changed into 

 Esperella, I so that we now arrive at the name Esperella 

 floreum, B. 



Our specimen was found encrusting a living Pecten oper- 

 cidaris, with a thin and rugged layer of greyish colour. 

 The thickness of this layer is about 1 mm. The skeleton 

 consists of megascleres and microscleres. The former are 

 styli (0"24 mm. by 0*008 mm.), which lie in irregularly 

 arranged and loose bundles. The microscleres consist 

 firstly of anisochelse, which are arranged in beautiful 

 rosettes. Similar structures are found in Esperella lin/y.a, 

 B.,§ in Joplion ahnormalis, Kidley and Dendy,; and in 



* Thos. Higgin, ''Report on the Porifera of the L.iM.B. C. District." In 

 " Fauna of Liverpool Bay, " vol. 1., p. 85. 



t Oscar Schmidt, " Si^ongienfanna des Atlantischen Gebietes, " 1870, j). 76. 



X Vosniaer, " Bronn's Klassen u. Ordn. d. Thierreichs, Porifera," }>. 353. 



§ Bowerbank, "British Spongiadie," vol. i., pi. xviii., fig. 297. 



II Ridley and Dendy, " Report on the Monaxonida, collected by H. M, S 

 Challenger," pi. xvii., fig. 7, 



