158 



HAPLOCECIA. 



M. romeri (Hag.), 1 are both typical members of this group. Reuss 2 

 has used the term in this sense, as has also Zittel. 3 It might be 

 convenient to accept Melicertites for this group of species, in spite 

 of the uncertainty as to the type form ; but the confusion in which 

 that genus is involved is inextricable ; and as the genus was 

 based on an erroneous interpretation of facts, it seems advisable 

 to drop it. Pergens has recently used the term in another sense, 

 and the one figure he gives of a member of this group appears 

 to me to be that of a Spiropora. 



The most important point to be determined in connection with 

 this genus is whether the form and position of the apertures, on 

 which the group of Melicertitina is based, are characters of any 

 great value. Some allied species have been referred to the 

 Cheilostomata, while Pergens places them in a distinct group of 

 Cyclostomata. In the first place, in regard to the lateral position 

 of the aperture : this does not seem to me a point of more than 

 generic value, even if it be always worthy of recognition to that 

 extent. In some species of Stomatopora, such as Stomatopora 

 dicfiotoma, Lamx. (see PL I. Fig. 2), the aperture is as truly 

 lateral and as restricted in size as it is in many of the Bryozoa 

 referred to the Melicertites group. The form of the aperture 

 appears to be due to the oblique truncation of the raised peristomes. 



In order to illustrate this point, two figures are given of different 

 parts of the same zoarium of a specimen from Ranville : Fig. lla 



FIG. 11. Two parts of one zoarium of Haplocecia straminea (Phil.), 

 X 10 dia. Calcaire a polypiers: Ranville. B. 4566. Showing 

 worn and unworn conditions. 



1 Ceriopora romeri, Hagenow, Mon. Rug. Kreide-Verst. : Neues Jahrb. (1839), 

 p. 285, pi. v. fig. 7. 



2 In Geinitz. Das Elbthalgebirge in Sachsen. Th. 1, pt. iv. Palaeont. Bd. xx. 

 Th. 1, p. 120. 



3 Handb. Palseont. Bd. i. Lf. 4 (1880), p. 606. 



