SYSTEMATIC ACCOUNT 153 



Thus it may be assumed that Collinge's specimens were of a medium size. 



A description and figure of the maxilliped was given by Collinge (p. 82 and pi. 8, fig. 25). A figure 

 of this appendage taken from a male specimen is included in the present paper (Text-fig. 4^*), together 

 with the basal portion of one taken from a breeding female (Text-fig. 4c). These figures illustrate a 

 sexual diflFerence in the form of the coxopodite characteristic of many isopods, that is, the development 

 in the breeding female of a coxal ' lobe ' which is curved and fringed with setae. 



A figure (Text-fig. 4 a) of the first brood lamella of the left side is also included to show another 

 characteristic isopod feature of the breeding female. This is the folding of the plate, the anterior half 

 of which partially overlies the mouthparts, the posterior half forming the anterior boundary of the 

 marsupium. It also shows the characteristic finger-like projection which extends inwards from near 

 the point of attachment of the lamella on to the coxopodite of the limb. 



Distribution. This species appears to be a fairly shallow-water form. Its range includes Table 

 Bay, the Cape of Good Hope, the Indian Ocean, South Australia, Auckland, New Zealand, Chile, and 

 Rio de Janeiro. 



Genus Synidotea Harger, 1878 



In the definition of this genus, both Stebbing (1902, p. 60) and Richardson (1905, p. 376) gave the 

 fusion of the epimera of the thoracic somites with their respective somites as a diagnostic character. 

 Stebbing pointed out that the last three thoracic somites were considerably shorter than the rest and 

 the ' demarcation of the side plates was very faint '. 



If only the dorsal surface of a species such as Synidotea hirtipes (Milne Edwards) is examined, this 

 definition might appear to be correct. Examination of both surfaces, however, shows that the 'epi- 

 mera' of the last three thoracic somites are coxal in origin, whereas those of the anterior somites are 

 pleural expansions of the terga. In the first four free somites the coxal joints of the limbs are clearly 

 defined, the outer margin of each is ring-like and, except in the first, is clearly marked off from the 

 ventral surface of the pleuron by a suture ; the inner margin is produced as a coxal plate which extends 

 to the mid-ventral line. 



I have examined specimens of two other species of this genus, S. nodulosa (Kroyer) and S. bi- 

 cuspida (Owen), and in both the form of coxae agrees with the condition found in 5. hirtipes. It is 

 probable that this character may prove to be common to all members of the genus. 



Synidotea hirtipes (Milne-Edwards, 1840) 



Idotea hirtipes Milne-Edwards, 1840, p. 134; Krauss, 1843, p. 61. 

 Edotia hirtipes Miers, 1881, p. 68. 



Synidotea hirtipes Benedict, 1897, p. 403; Stebbing, 1902, pp. 59-62; Stebbing, 1910, p. 434; Omer-Cooper, 1926, 

 p. 205. 



Occurrence. Houtjes Point, Saldanha Bay, at anchor, 25. v. 30, 12 m., i immature specimen. 



Remarks. The Discovery collections contain a single specimen measuring 19 mm. in length and 

 8-5 mm. in greatest breadth. 



The description of this species is already well known ; my observations with regard to the second 

 pair of thoracic appendages agree with those of Stebbing (1902, p. 60); he pointed out that they 'are 

 shorter and stouter than the rest and the penultimate joint is considerably expanded to form with the 

 terminal one a prehensile hand '. To a lesser extent an expansion of the penultimate joint is also 

 noticeable on the next three pairs of limbs. 



Distribution. This species is a shallow-water form recorded from depths varying from 12 to 

 69 m. The original specimens described by Milne-Edwards were collected from the coast of the 

 Cape of Good Hope ; Stebbing's material was collected from the coastal waters around Cape St Blaize 



