268 



DISCOVERY REPORTS 



Specimen 6. Infundibular, 15 cm. high, 9 cm. across. Outer surface thrown into 

 strongly developed rounded ridges. Colour dark brown (Plate XLVIII, figs. 5-8). 



Specimen 7. Flabelliform, one surface pore-bearing with spinose processes : the other 

 bearing oscules. Colour yellow (Plate XLIX, figs. 2-3). 



With the exception of specimen 7, all have a deep cloaca with oscules measuring up to 

 4 mm. in diameter. The series also shows that the species has a range of form very like 



Fig. 6. Series showing external form in the smaller specimens oi Haliclona bilamellata, sp.n. 

 Dotted lines indicate shape and position of cloaca. 



that of Haliclona dancoi {sensu Burton, 1929, p. 420), and differs from that species only 

 in texture and the size of the spicules. 



While the external form is similar in every case, two types of skeleton are found. 

 In some specimens it is chalinoid and consists of a quadrangular network in which the 

 primary fibres contain a double row of spicules coated with a thin layer of spongin and 

 the secondary fibres contain one spicule only, the primary fibres being only one spicule 

 length apart. The oxea in these forms vary from 0-132 to o-i8 by 0-007 to o-oo8 mm. 

 In the remaining specimens, the skeleton is pachychalinoid and consists of a quadrangular 

 network of stout primary fibres, containing from eight to ten spicules serially arranged, 

 but with very little spongin, and secondary fibres containing three or four spicules. The 

 meshes of the network are from 0-3 to 0-4 mm. across and the spicules 0-240 by 0-0 1 mm. 

 This separation into two types is, however, more apparent than real, for in the second 

 group the skeleton may, in places, be identical with that of the first group, so that we 



