J. Allan Thomson — Brachiopod Nomenclature. 411 



2. Palaosoma robustum (Baldwin), char, emend, infra. (Text- 

 fig. 3; PI. IX, Fig. 2-4.) 



Syn. : Euphoberia robusta, Baldwin, Geol. Mag., 1911, pp. 77-8. 

 E. armigera, Meek & Worthen, Baldwin, ibid., p. 77. 

 E. icoodwardi, Baldwin, ibid., pp. 78-9. 



Not stn. : Euphoberia armigera, Meek & "Worthen. 



Length of anterior seven segments, 22 mm. ; breadth of parallel-sided 

 segment (19th from head) 14 mm. ; head rounded ; eyes present, ocelli in 

 a group, antennae closely adjacent to the eyes ; prozonites smooth, metazonites 

 slightly convex from side to side, divided by transverse groove into an anterior 

 third and a posterior two-thirds, the groove deep near the median line, 

 becoming shallow laterally, disappearing just before reaching the lateral 

 border ; lateral expansions narrow and backwardly directed ; spine-bases as in 

 preceding species. 



Type : L 9943, Man. Mus. 



We have made no attempt in the above study to indicate the 

 systematic position of our new genus, but it is our intention to do 

 so in a later paper, which will deal at some length with the 

 classification of certain fossil forms. 



EXPLANATION OF PLATE IX. 

 FIG. i. — Palceosoma giganteum (Baldwin sp.). Genoholotype x 0-79. Cast of 



posterior end of the body (L 9941, Manchester Museum). 

 ,, 2. — P. robustum (Baldwin sp.). xl-36. Impression of some fourteen 



posterior segments (L 9944, Manchester Museum), showing 



tergites, pleurites, and walking legs. 

 ,, 3. — P. robustum (Baldwin sp.). Holotype x 1-5. Cast of anterior end of 



the trunk (L 9943, Manchester Museum). 

 ,, 4. — P. robiistum (Baldwin sp.). x 0-76. Impression of the head and cast 



of some thirty-eight body segments. (In collection of H. Howard, 



Bochdale.) 



TV. — Brachiopod Nomenclature : Clavigera, Hectoria, 

 Rastelligera, and Psioidea. 



By J. Allan Thomson, M.A., D.Sc, F.G.S., Director of the Dominion 

 Museum, Wellington, New Zealand. 



IN dissenting from Dr. C. T. Trechmann's procedure in rejecting 

 the name of Clavigera for certain New Zealand Mesozoic 

 Spirigerids and proposing the new name of Hectoria instead, I would 

 like first to express the appreciation of New Zealand geologists for 

 the painstaking work of Dr. Trechmann on the Trias of New 

 Zealand. 1 



The reasons for his rejection of Clavigera are thus stated : 3 

 " Clavigera represents a group of specialized bisulcate Spirigerids the 

 affinities of which are discussed later on. I have considered it 

 advisable to rename this group, "and have called it Hectoria. Hector's 

 description was published without any illustrations, and his sub- 

 generic name closely resembles that of Claviger given to a group of 

 the Melanias." 



The close resemblance between the names of Claviger and Clavigera 



1 C. T. Trechmann, " The Trias of New Zealand " : Quart. Journ. Geol. 

 Soc, vol. lxxiii, pp. 165-246, 1918. 



2 Loc. cit., p. 216. 



