18 U.S. NATIONAL MUSEUM BULLETIN 2 78 



50-| 



48- 



^ 42A 



^38- 



t 



3h 

 32- 

 30 





Jan. ' Feb. ' Mar- ' Apr- ' May 'June 'July ' Aug. 'SV/V. ' Oct. ' Nov. ' Dec. ' 

 Figure 7. — Aeginina longicornis, monthly and latitudinal distribution of ovigerous females. 



Caprella Lamarck, 1801 



Flagellum of antenna 2 biarticulate, swimming setae usually pres- 

 ent; mandibular palp absent, molar present; outer lobe of maxilliped 

 larger or equal to inner lobe; gills on pereonites 3 and 4; pereopods 

 3 and 4 absent, pereopod 5, 6-segmented; abdomen of male wath pair 

 of appendages and pair of lobes, female with pair of lobes. 



Type-species: Cancer linearis Linnaeus, 1767 (subsequent designa- 

 tion by Dougherty and Steinberg, 1953). 



Kemarks. — Mayer (1890, p. 107; 1903, p. 73) states that it is un- 

 necessary to study in detail the mouthparts of members of this genus 

 since the specific differences stand out much more clearly in other 

 characters. I agree with this statement, hence, I have not included 

 descriptions of the mouthparts other than the lacinia mobilis of the 

 right mandible except for those appendages which exhibit variation. 

 The typical mouthparts of Caprella may be characterized as follows: 

 Mandible with 5-toothed incisor; left mandible with 5-toothed lacinia 

 mobiUs, right variable; setal row of left mandible with 3 serrate 

 setae, right wdth 2 serrate setae; molar present with single small 

 plumose seta. Outer lobe of maxilla 1 mth 7 spines, palp wdth variable 

 number of spines and setae. Lobes of maxilla 2 usually densely setose. 

 Outer lobe of maxilhped wdth row of spines on medial margin and 

 usually covered with numerous setae; inner lobe flattened apically 

 with several spines and numerous simple and plumose setae; articles 

 of palp usually heavily setose, grasping margin of dactylus finely 

 toothed or serrate. 



