NEW hl'KOlKS i>K ('lvA\V[,lNi; MKIUSA KKO.M Al'SII.'AI.IA liKlUdS. SJ7 



Altlioii^li its liyilitiiil sta<,'e is at ])rL'seiit luikiuiwii, tlie Medusa from 

 Port Jackson is i-ot'eried to Gilchrist's ireims ('iiiilniiriini, and is described 

 as a new species dift'erini;' in several well-marked characters from the 

 crawling Medusic of the Southern Hemisphere. The ludotype ( Heg. No. 

 Y. 586), and slides of serial sections of the ^ledusa have been deposited in 

 the Australian Museum, Sydney. 



I have much pleasure in associating the name of Professor W. A. 

 Haswell with this new species of crawling Medusa fi-om Port Jackson, 

 Australia. 



CnIHOXK.MA ItASWELLl, sfi. HOC. 



(PI. xvii., figs. 1-4; PI. xviii., figs. 1-5.) 



Exh-nial i.-liaracters. — The largest specimen, when fully expanded, 

 measured 3'5 mm. from tip to tip of the tentacles. When viewed from 

 above, the umbrella appeal's circular with a diameter of 12 mm. None 

 of my specimens are as large as the Kerguelen species, which, accoi'ding to 

 Vanhoft'en, measured 5'5 mm. in breadth in the pi'eserved cimdition. In 

 the Cape species the breadth of the largest male was 3"3 mm. 



In a lateral view of the Medusa, the body appears very slightly flattened; 

 it is not so com[)ressed as in either (_'. rKjteiise, in which the height is about 

 one-third of the breadth of the body, or in C. }iod<j!^i))u\ which is consider- 

 ably flattened, the height being about one-fourth of the diameter of the 

 disc. In tlie preserved condition, howevei-, there is a marked change in 

 shape, some of the specimens appearing much nnne flattened than in life, 

 while others are almost spherical in outline. 



Thei'e is a considerable degree of variation in the colour exhibited by 

 individuals of different ages. The young Medusa^ are not heavily 

 pigmented and hence appeal- lightei- in colour than the mature specimens. 

 When viewed by transmitted light the body of the adult is, in most cases, 

 a reddish-yellow colour, but appears bright red or orange by reflected 

 light. This colouration is due to the presence of masses of pigment- 

 granules in the endodermal cells of the stomach and the circular canal. 

 In the specimen figured (PI. xvii., fig. 1.) there is in the centie of the disc 

 a large reddish-yellow area, which is roughly octagonal in outline 

 with eight radiations extending to the circular canal. In none of 

 my specimens do these ladiations become enlarged into saccular structures 

 such as Gilchrist figures in ('. C(ipe)iHe. 



On the exumbrellar surface above the reddish-yellow stomach is an 

 octagonal ring which appears cream coloured when viewed by reflected 

 light. In one specimen the octagonal ring was absent, but eight broad 

 radiations of a deep cream colour were present which extended to the 

 circular canal concealing the radiating lines of the stomach. 



The gonads vaiy in colour from cream to pale yellow and lie around 

 and above the reddish-yellow stoniacli, leaving only a small circular patch 

 of stomach visible in the centre of the disc. 



