4 Dr. G. Lindstrom on the Affinities 



lias not the loast relationshij) to tliat of the Hellolitidje. In 

 its s])ongiosc mass there are no calicles ])ropcr, clearly circiun- 

 goribed by a wall of their own ; nor are there any septa. The 

 animal is sheltered in an irregular tube of the general mass, 

 the texture of which is such that the coral, if Anthozoan, would 

 have to be placed amongst the Perforata. According to the 

 observations of botli L. Agassiz and Pourtales*, the animal 

 of yfillcpora is a true Hydrozoon ; and although the latest 

 researches of Moseley (' Nature,' vol. xiii. p. 138) seem to 

 leave it undecided whether it is truly Hydrozoan or Anthozoan, 

 I think it better to remove the genus from the Anthozoa — the 

 more so as the above naturalists, who alone have described the 

 animal in its living state, are of this opinion f- At the same 

 tunc we mav discard all conclusions that might be drawn as 

 to the systematic position of the supposed relations of Millc- 

 jwra. Through the researches of Verrill J, it is known that 

 the animal of PociUopora in no way resembles tliat oi MiUeporaj 

 but that the former is a true Anthozoan, akin to the Oculinidse 

 and Styhphora. 



The Silurian genus Labechia, E. & H., also seems to partake 

 of Hydrozoan characters. In its earliest stages of growth 

 this fossil consists of a very thin circular disk, with concentric 

 lines of growth beneath, and having the superior surface studded 

 with blunt spines, which radiate from the centre, and also coa- 

 lesce and form continuous ridges. In this state it reminds one 

 of nothing more than the sclerobasis of the Hydrozoan genus 

 Ilydractinia ; and the only difference seems to be that Lahechia 

 is entirely calcareous, whilst Ilydractinia is corneous. During 

 the course of growth the primitive disk of Lahechia is increased 

 in thickness by the addition of successive thin strata, which 

 closely conform to the subjacent fundamental crust, being ele- 

 vated where the spines are situated. As these successive layers 

 leave a small space between them, and are in themselves very- 

 thin, they give rise to a false appearance of tabulae. Milne- 

 Edwards considers (Hist. Nat. Cor. iii. p. 284) that the spines 

 are projections upwards from the rim of the supposed calicular 

 wall ; but there is not the least trace of any wall circum- 

 scribing any calicle, or of any septa, and these spines are 

 only the last ones of the uppermost stratum superimposed on 



* Pourtales, " Deep-Sea Corals,'' Illustr. Cat. Mus. Cambr. no. iv. p. 56. 



t If, as Dr. Duncan states, in consequence of the last researches of 

 Mr. Moseley ('Nature,' April 13th, 1876j, Milleporn is really an Antho- 

 zoan, it deviates in a high degree from other Corals, and can by no means 

 be allied with the Heliolitidse. 



\ " Review of Corals of W. Coast of America," Trans. Conn. Acad, 

 vol. i. pp. 2, o23. 



