On two new Isopods from New Zealand. 415 



lateralia brachiorum simulantibus maxime prolatis. Brachia 

 incipientia ab angulis disci producta, series radiales continuantia. 



In superficie actinali os medium, decern magnis ossiculis oralibus 

 cinctum, prostantibus scutellis adoralibus. Unum scutum buc- 

 cale adest ; denies, scutella oralia et tori angulares absunt. 

 Papillae orales ternae aut quaternae, cum una magna, ad angulos 

 oris apposita. 



Series scutorura quadratorum a rimis oris per radios procedunt, 

 scutellis ventralibus prostantibus, et per brachia inchoata pro- 

 ducuntur. 



Foramina pedum ambulacralium septis angustis disjuncta, per- 

 magua, protecta singula longa papilla ambulacrali ad margines 

 interbrachiales, lanceolata et squamaeformi, altera miuore ad 

 partem interiorem radii juxta scutella brachiorum ventralia posita. 

 Areas interbrachiales squamis parvis hexagonalibus obtectae ; mar- 

 ginem appropinquantes decrescunt, relinquentes limbum angustum 

 expositum ; disci margine cincto densis spinis brevibus et com- 

 pressis. 



Ha b. in mari ad oras insula Madagascar. 



EXPLANATION OF PLATE XX. 



Fig. I. Astrophiura permira, nobis, abactinal aspect, x 6 - o. 



Fig. 2. Actinal aspect of the same specimen. X 6*5. 



Fig. 3. Brachial series of radius ii, abactinal aspect. X 10. 



Fig. 4. Brachial series of radius v, abactinal aspect, x 10. 



Fig. 5. Actinostome : mouth-armature. X 10. 



Fig.Q. Pore-area and actinal aspect of radius iii. X 10. 



Fig. 6 a. Terminal portion of pore-area and actinal aspect of radius ii. 



X 10. 

 Fig. 7. Transverse section, showing the proximal extremity of the fifth 



segment in the brachial disk-series of radius iv. x 10. 

 Fig. 8. Transverse section, showing the distal extremity of the fourth 



segment in the brachial disk-series of radius iv. X 10. 

 Fig. 9. Distal extremity of the first free segment of the rudimentary free 



arm of radius iv. X 20. 

 Fig. 10. Distal extremity of the fourth segment of the rudimentary free 



arm of radius v. x 20. 



XLVI. — On two new Isopods (Arcturus, sp., and Tairais, 

 *p.) from New Zealand. By George M. Thomson. 



[Plate XIX. figs. 1-6. J 



The two new species of Isopods described in this paper re- 

 present genera not. hitherto found in New Zealand ; and they 

 are both somewhat remarkable for their resemblance to, and 

 dissimilarities from, already known species. Both forms were 



