studies on marine Ostracods 



739 



The first two of these species, E. Chierchiae and E. aculeata, are certainly rather closely 

 connected to each other; on the other hand they show rather far-reaching differences from 

 E. lacunosa and E. d' Arcy- Thompsoni. It is rather difficult to say anything certain about the 

 relation between the two last-mentioned species, partly because the male of E. lacunosa is quite 

 unknown, and partly because of the incompleteness of the descriptions. But it seems to me 

 not improbable that they are fairly closely related. These reasons also make it impossible 

 to decide whether these two species are to be distinguished as the representatives of a 

 special sub-genus; it seems, however, fairly probable that future investigations will make 

 this necessary. 



First antenna: G. W. Muller, in his work 1906 a, states that this antenna is five-jointed 

 in the male, ,,die Grenze zwischen dem 3. and 4. Glied ist schwer zu erkennen'". In his work 

 of 1912 this writer states that this antenna is four-jointed: ,,1. Antenne des cJ mit 3 liingeren 

 Gliedern und einem 4. sehr kurzen Gliede". In the latter work it is obvious that the third and 

 fourth joints are taken as one joint. As wiU be seen above, I have adopted the former view in 

 the genus description, because in the species investigated by me the two last-mentioned joints 

 were distinctly separated; the fourth joint (sensu meo) was even moved by several special muscles. 

 This same author writes in his work, 1890 a: ,,die Borste des zweiten Gliedes fehlt iiber- 

 luiupt; an der Stelle, wo sie beim Weibchen von Conchoecia steht, findet sich eine flache Grube, 

 welche auf ihre friihere Existenz an dieser Stelle hinzuweisen scheint." It was unable to observe 

 any such cavity; it seems to me not at all impossible that this is a mistake on the part 

 of this writer. 



In the diagnosis of this genus, 1906 a, p. 127, G. W. MOlleu states that from the third 

 joint of the first antenna of the males ,,ragt ein hakenartiger Fortsatz in das 4. hinein; derselbe 

 licgt medial; ist nicht immer gleich deutlich. Ich habe keine voUe Klarheit iiber seine Lage 

 und Bedeutung gewinnen konnen. Anscheinend liegt er im Innern des Gliedes, dient dem ^luskel- 

 ansatz." — I was not able to observe any such chitinous process on the specimens of this genus 

 that were investigated by me. It does not seem impossible, however, that this is a mistake 

 on the part of G. W. MCller. The ventero-medial part of the wall of the fourth joint in the 

 male first antenna of E. Chierchiae is rather strongly chitinized. The dorsal bomidary of this 

 part is indicated in the adjoining fig. 12 by a bne running longitudinally at about half the height 

 of the joint. Does this part correspond to the process mentioned by G. \V. Mt'LLER? This does 

 not seem impossible to me; its medial position is in favour of this; as is shown by the above 

 quotation, G. W. MCller himself was not quite certain whether the process in question was 

 really situated inside the joint; its medial position, on the other hand, was quite clear. (This 

 process is not mentioned in this author's work of 1912.) 



Mandible: To judge from pi. X, fig. 7, G. W. Mt'LLER, 1908, E. lacunosa shows, 

 with regard to the structure of the pars incisiva of the coxale, a type quite different not only 

 from E. Chierchiae, described below, but from all the forms hitherto known in the family Halo- 

 cypridae. G. W. MCller's repnxluction and description of this organ are, however, so incomplete 

 and indistinct that I did not think it right to pay any attention to this information in working 

 out the genus and sub-family diagnoses. 



Relations beWeen 

 the species. 



First antenna. 



Mandible. 



