EEPORT ON THE ISOPODA. 55 



however, about these appendages is the total absence of any mandibular palp, a fact 

 which at once distinguishes this species from its congeners. It is stated by Sars that the 

 genus Macrostylis is characterised, among other peculiarities, by the want of a mandibular 

 palp, which is also occasionally absent in Ilyarach na and Desmosoma ; this fact made 

 me hesitate before including the present species in the genus Munnopsis. 



The shape of the mandible, apart from the absence of a mandibular palp, is not unlike 

 that of Eurycope gigantea, or indeed of Munnopsis typica. 



The maxillse I am quite unable to describe, as they were hidden by the maxillipcdes ; 

 the value of the results likely to be obtained by figuring and describing these appendages 

 did not appear to me to be at all commensurate with the injury to the unique specimen 

 which would be caused by unmounting it and teasing out the appendages. 



The maxillipedes again are unlike the typical form of these appendages in the 

 Munnopsida generally, owing to the unusually large size of the third joints of the palp. 

 One of these appendages is displayed in fig. 9 ; along the margin of the stipes are 

 two sensory processes. 



The thoracic appendages of the first four pairs appear to be similar in structure, but I 

 am unable to speak with anything like certainty, because only three of these limbs were 

 preserved, the first and second on the left side and the second only on the right hand side 

 of the body. 



The first appendage is displayed in figs. 5 and 6 ; the first pair of appendages are 

 more slender than the second, but otherwise are more or less similar in form ; the first 

 joint in each is the longest, the second is somewhat shorter, and the third is extremely 

 short ; this joint and the next two are beset with stiffish hairs, which appear to be 

 proportionately stronger in the first appendage than in the second. 



The third and fourth appendages on both sides of the body were broken off close to 

 their articulation ; they are evidently larger than the preceding appendages ; they also 

 appear to resenrble the same appendages in Munnopsis typica in the shortness of the 

 proximal joints of the third and fourth thoracic appendages as compared with the two 

 preceding limbs. 



The three posterior pairs of thoracic appendages (fig. 7) resemble those of other 

 Munnopsidse in the modification of the distal joints ; these, however, do not seem to 

 be so much widened and flattened as in other species. 



The uropoda (fig. 11) are short and uniramose ; they are two-jointed, the distal joint 

 being longer than the proximal although more slender. 



Although I believe I am right in assigning this species to the genus Munnopsis, it 

 differs in many important particulars from Munnopsis typica. The most striking- 

 difference perhaps is in the absence of a mandibular palp ; but as this structure is not 

 always constant in a particular genus (it is for example sometimes absent and sometimes 

 present in Desmosoma) its absence in Munnopsis australis does not necessitate the removal 



